The purpose of this guide is to provide simple factsheets on priority invasive alien pests that currently threaten plant health, human health and/or biodiversity in the Pitcairn Islands (Pitcairn, Henderson, Ducie and Oeno Islands), a UK Overseas Territory located in the southern Pacific Ocean. It also identifies the main pathways of introduction so that biosecurity inspections can be targeted. The guide is intended to be used by those working in biosecurity, and by all those interested in preserving the unique environments and biodiversity found in the Pitcairn Islands.